help! Htc Desire Telus unlocking question..

I have a TELUS HTC Desire and I no longer want to pay their ridiculous prices for their plans, I do however love my phone and want to keep it.

I want to switch companies and move to either mobilicity, wind or koodo...basically for the waaaay cheaper rates. After much searching, I am still unsure about which companies use which networks and which companies would be compatible with the network the phone is on. Wanting to do this asap. Any help would be much appreciated.